1. Field of the Invention
The invention relates generally to the field of digital data processing systems, and more specifically to mechanisms for diagnosing faults and errors in such systems.
2. Description of the Prior Art
Over the past several years, the importance of the availability of computers to government and industry has increased markedly. Computers have been developed and adapted for use not only in fairly conventional activities such as bookkeeping, accounting and inventory control activities but also in more esoteric areas as design, engineering, and manufacturing. Computers have also been adapted for use in many office activities such as document generation using word processing and graphic design. Access to computerized databases, either on-site or over telephone lines, is also important in knowledge-intensive activities.
In attempting to fulfill the ever-increasing demand for both processing power and sharing of information among users, individual computers are being made faster and more complex, and multiple computers are being linked in clusters or networks to facilitate sharing of data and resources, such as telecommunications links, printers, and so forth, among users. As such computer systems increase in complexity, the likelihood of a failure, either in hardware or in software, also increases. A number of strategies have been devised to minimize disruption, as well as service costs, which may occur as a result of a failure. Typically, however, such strategies rely on the occurrence of a failure, which may be manifested by a user noticing a disruption in service or, potentially more disastrous, the loss of data. At that point, a service technician normally attempts to identify the failed component and repair it, which can require several service trips to the computer site and extensive running of diagnostic programs to identify the failed component. Thus, the repair process may be somewhat costly, not only in service charges but also in the fact that the computer is either not available or provides only a degraded level of performance.